There are some european manufacturers that produce TT narrow gauge. TTm is TT meter gauge running on N scale track and TTe which is narrower gauges running on Z scale track. I've been eyeballing some Czech kits (of course) for a future branch line. Here are a couple links to DK-Model. Sorry the whole thing is Czech or German only. Click on the pictures for a close up (especially the steamer in the first link, you get to see how they did the mechanism).http://www.dk-model.cz/tt-ul.htmlhttp://www.dk-model.cz/tt-uo.htmlhttp://www.dk-model.cz/tt-un.html